Blank cartridge devices have been known for some time due to U.S. Pat. No. 3,744,370. This known blank cartridge device consists of an almost rectangular, oblong frame having a laterally open recess in its rear transverse side (in further explanations, “front” and “rear” always refer to the firing direction). The frame is sized to be pushed from the side over the muzzle flash eliminator of the firearm. The recess in the rear transverse side thereby engages in the exterior ring groove on the muzzle flash eliminator.
A threaded bush is introduced in the front transverse side. If the frame is placed on the muzzle flash eliminator in the manner described, then the axis of the threaded bush aligns with the bore axis of the barrel.
The nozzle body is now inserted into this threaded bush from the front and its male thread is screwed into the internal thread of the threaded bush until its rear end sits securely on the muzzle. A removable transverse pin in the front end of the nozzle body serves as the tool for tightening the thread so that the blank cartridge device is clamped tightly on the muzzle flash eliminator.
The tapped blind hole connects directly to the barrel hole and ends where the spray hole pushes through the wall of the nozzle body. The spray hole then lies within the muzzle flash eliminator, but is arranged in such a manner that it can blow outwards unimpeded through the slits of the muzzle flash eliminator.
Overall, the known muzzle flash eliminator should be implemented in a manner so that it is strong enough to withstand a shot, if by mistake a live cartridge, instead of a blank cartridge, is fired. Splinters may occur if the nozzle body should break, and these fragments can escape through the slits in the muzzle flash eliminator. Fine metal splinters from the shell can also escape straight through the nozzle hole when firing with blank cartridges and can cause injury in some cases.
The mounting is also not ideal because a special tool, which can be lost, is required to tighten the thread. However, if the nozzle body is loosened during shooting then the combustion gases from the discharged blank cartridge flow past the nozzle body and particles can be shot out. Certain blank cartridges (those with wood projectiles, for example) tend to release splinters that can still be extremely dangerous right in front of the muzzle.
In any case, a jam is caused when a vapor recovery system, for which the nozzle hole is aligned, is needed for the firearm to function properly. A loose-fitting blank cartridge device ensures the escape of some gas so that the firearm can be easily charged.
Many of these disadvantages are addressed by a blank cartridge device as described in DE 197 29 565. However, this improved blank cartridge device is very costly to manufacture.